A typical application for corresponding methods and apparatus is a mail routing station: In a mail routing station, packages of widely different sizes are delivered on conveyor belts which are generally designed to take packages up to a set maximum size, although all of the packages do not necessarily have to be of the maximum size. The present invention should not, however, be limited to mail routing stations, but can also be used in production methods comprising sorting and routing stations or the like. For better comprehension, however, the following description primarily refers to the example of a mail routing station. Prior art methods and apparatus of the type described above are known but only with quite definite limitations. Conventional video cameras are not capable of completely capturing articles with extensive surfaces with sufficient resolution to sufficiently clearly recognise, i.e., with the required resolution, information which appears on only a very small region of the article with an extensive surface.
When video cameras have been used in such stations, they have been restricted to applications for which it was certain that the surface area of an article carrying the necessary information for identification and allocation thereof always passed through a set field of view which could be relatively small compared with the whole of the surface of the article facing the video camera. In practice, the method could thus only be used for standard packages which always had an address label or the like in the same region of the package, and wherein the packages always had to be arranged in the same orientation and position on a conveyor belt or the like. Such a method is still applicable for mail order operations, for example, which use standard size packages with standardized packaging, so address labels always have the same size and positioning on a package. Further, packages of a single size can be placed on one conveyor belt so the camera is always the same distance away from the surface of the package. These conventional methods are, however, not suitable for mail or other commercial courier services which receive packages from the public or at least from different clients and carry them to a different address. Such packages are standardized only in that they cannot exceed a set maximum size. A widely accepted standard, for example, is a maximum height and width of 900 mm; in some circumstances the length can exceed this value. In general, such packages are parallelepipedal in shape and have a flat surface bearing the address, handling information or information regarding the contents (breakage risk, right way up when transporting, or in storage), and the type of carriage (for example express mail). In addition, information regarding the sender can also be present on the surface of the package. Neither the size nor the arrangement of this information on the surface of the package is clearly fixed. Further, some of this information or additional information can be presented on the surface of the package in the form of a barcode.
Prior art methods and apparatus for such packages involved a person standing by a conveyor belt who looked at the package and inputted the information on the package directly into a terminal or the like located near the conveyor belt. A barcode reader could also be used.